(Reuters) —Mylan Inc on Thursday sued Celgene Corp to
stop the latter's effort to keep generic versions of two drugs that
generate $4.5 billion of annual sales off the market.

The lawsuit accuses Celgene of maintaining unlawful
monopolies over Revlimid, which treats disorders caused by poorly
formed blood cells; and Thalomid, which treats lesions associated
with a variation of Hansen's Disease, or leprosy.

Revlimid is a branded version of lenalidomide, and is a derivative
of thalidomide, a drug introduced in the 1950s for which Thalomid is
a branded version. Mylan said both drugs can cost more than $100,000
for a year's supply.

In its lawsuit filed in the U.S. District Court in Newark, New
Jersey, Mylan accused Celgene of using federal limits on the
distribution of Revlimid and Thalomid, which were designed to
promote the drugs' safety, as a pretext to keep generic drug makers
from obtaining their own samples.

Mylan said this prevents generic drug makers from conducting
"bioequivalence" tests required by U.S. regulators before generic
drugs can be launched.

"The effect of Celgene's conduct is that no generic manufacturer,
including Mylan, has been able to bring generic versions of Thalomid
and/or Revlimid to market," Mylan said. "Through its illegal
actions, Celgene has foreclosed Mylan from even attempting to enter
the market."

Greg Geissman, a Celgene spokesman, declined to comment. Celgene is
based in Summit, New Jersey, and Mylan is based in Canonsburg,
Pennsylvania.

The lawsuit seeks to force Celgene to sell Mylan enough Revlimid and
Thalomid at market prices to allow for bioequivalence testing. It
also seeks compensation for Mylan's inability to sell generic
versions of both, and triple damages.